Impeller for rotary blowers.



No. 678,480. Patentedfluly l6, I90l.

T. W. GREEN.

IMPELLER FOR ROTARY BLOWERS. (Application filed July 17, 1900.)

' (No Model.)

WITNESSES: Y INVENTOR Mxgxwo I J" I y S .{TO RNEY v i UNITED STATES PATENT O FICE.

THoM .=.-w.' ennENf, on PHILADELPHIA, PENNSYLVANIA, ASSIGNOR To THE WILBRAHAMBAKERBLOWER COMPANY, :OF SAME PLACE.

,IM'PELLER FOR ROTARY BLovvERs,

- sPEcrmcnmIoii forming part'ofLetters Patent No. 678,480, dated my 16,1901.-

. Application iiled July 17 1900. Serial No. 23,873. (110' model.)

Toad-whom it may concern: a p r Beitknown that I, THOMAS W. GREEN, :1

. citizen o'f'the United States,residing at Philadelphia,'in the county'of Philadelphia and 5 State. of Pennsylvania, have invented new and useful Improvements in the Impellers of Rotary Blowers, of. which the following is a specification. p

'My, invention relates'to theimpellers of roio taryblowers or exhausters; and the object of my improvement 'is'to make a secure lock or cut-off on the impellers with the least possiblefinishing of the parts and at the same.

time get the greatest inward reach to each impeller.

the parts of each impeller that cooperate to make the cut-cits are formed to the shapes and in the manner hereinafter shown. The general construction of this class of blowers being well known, I havezshown only the impellers and the case surrounding them. 1; In the accompanying drawings, Figure lis a vertical sectional view through the middle -of the blower, showing the wings of one im- 2 5 peller at right angles to the wings of theother impeller and the lock or cut-ofli formed by the end of one impeller and the middle or waist portion of the opposite impeller. Fig. 2 is also avertical sectional view through the middle of the blower, but with theimpellers turnedfarther around and showing the end of the wing of the one impeller leaving the waist portion of the. opposite. impeller and the other parts. commencing to form the lock or cut-oft.

A is the outer casing, surrounding thefimpellers of the'blower. B B are the wings of the impellers.

A A are the circular end. headpieces se- 0 cured on the ends of the impellers. These end pieces are preferablycast separate from the wing portion, so that the locking portions of said impellers can be more easily finished.

a a are the finished segmental extensions of the impeller,operatin-g together to form the cut-off at times when said cut-off .is not being maintained by'one of the extensions or ends 1) operating with one of the segmental waist portions 0 of the impellers. All of the segmental extensions or are finished to the arc of a circle having a diameter equal to one= To accomplish the desired result,

fourth of thelength of one of the sides of the largest square 12 3 4 that can be inscribed in the circles O C, whosediameters are equal to the distance between the centers of the driving-shafts upon whichv the impellers revolve: These circles C 0 correspond to the pitch-line of the gear-wheels used on machines of this class. To describe the circles uponwhich the arcs of the segmental extensionsa a are struck, one point of the compass rests upon the circumference of the circle'C at one of the points d. The circle upon which the waist or middle portions 0 of each impeller are finished is struck from one of the points'e in themiddle of one of the sides of the inscribed square, and the radius of this circle is obtained by finding the point where a circle struck from. the point EfWOllld intersect thecircle struck from the point (1. When the waist portion of each impeller is formed to circles, as described, and the segmental extensions 0, are. finished, as herein shown, two of these extensions 0. will operate together to form alock or cut-off until one of the extensions or ends 19 of one of the impellers begins to cooperate with one of the segmental waist lines o of the opposite impellers These parts will then in turn form the lock until two of the. segmental extensions abegin again to cooperate, and so on the lock is continuously maintained by the segmental extensions a alternating with the parts I) and the segmental 'waist-lines c of the impellers.

Having thus described my invention, what I claim as new, and'desire to secure by Letters Patent of the United States, is-

1. In a rotary blower, the combination of two coacting impeller-blades,'each having oppositely-arranged locking parts and a look intermediate said locking parts, all so constructed and arranged as to shape and length, that both sets of said oppositely-arranged locking parts may be out of engagement at the same time but that during such disengagement an engagement of the two impellerblades will be maintained between said 0ppositely-arranged locking parts by the inter-. mediate lock, after one set of the oppositelyarranged locking parts has been released and before the other set becomes engaged.

2. In a rotary blower, the combination of two coacting impeller-blades having waist portions and provided with oppositely-arranged locking parts, which may be out of engagement at the same time, and locking parts on the ends of each impeller-blade, said locking parts being'all so constructed and arranged as to shape and length, that a lock is maintained between the two impeller-blades by the engagement of the locking parton-the parts being soconstrueted and arranged, as

to shape and length, that a lock will bemaintained by. the locking part on the end of one impeller-blade and the waist of the opposite impeller-blade, when the oppositely-disposed locking'parts are out of locking position.

4. A rotary blower having each of the impellers provided with four segmental extensions a, said segmental extensions being.v

formed to the arc of a circle having aTradius equ'al to one-fourth of the length of theside arc of a circle that is struck from the point e,

on' the middle'of theside of the inscribed square 1, 2, 3, 4, and has a radius equal to .of the greatest square that can be inscribed 3o the distance from the point e, to the nearest 0 points on one of the segmental extensions (1, whereby the segmental waist-lines c'c, cooperate with the extensions b b, to form a lock or cut-off during the interval when the segmental extensions (1 a, are not cooperating, substantially as shown and described.

In testimony whereof I aflix my signature in presence of two witnesses.

' THOMAS W..G-REENL Witnesses! Tnos. D. MowLDs,

SAML. lI. KIRKPATRICK. 

